The solar cells utilizing sunlight have been drawn attention as an energy resource to replace a fossil fuel such as petroleum, coal and natural gas or the like. At present, an efficiency enhancement is actively studied on silicon solar cells using crystalline or amorphous silicon, or compound semiconductor solar cells or the like using gallium, arsenic or the like. These solar cells, however, require high energy and cost to produce, and thus there was a problem that it was difficult to use generally.
In addition, the photoelectric conversion devices using dye-sensitized semiconductor particles, or solar cells made by using the same have been known, and a material and a production technology required for preparation thereof have been developed and disclosed (refer to Patent Literature 1, Non-patent Literature 1 and Non-patent Literature 2). These kinds of photoelectric conversion devices are drawn attention because they are produced using relatively inexpensive oxide semiconductors such as titanium oxide, and they have a possibility to yield lower cost photoelectric conversion devices than conventional solar cells using silicon or the like, and also to yield the colorful solar cells.
In the dye-sensitized type photoelectric conversion devices now under development, however, the ruthenium-based complexes are used as sensitizing dyes to obtain the photoelectric conversion devices with high conversion efficiency; cost of the dyes themselves is high and a supply problem is also left. In addition, use of organic dyes as sensitizing dyes is also challenged, however, practical application level has not yet been attained because conversion efficiency, stability and durability are still low, and thus further enhancement of conversion efficiency is desired (refer to Patent Literature 2). Up to now, the preparation examples of photoelectric conversion devices using a methine dye are known, and in addition, relatively many study examples are known on coumarin-based dyes (refer to Patent Literature 3) or melocyanine-based dyes (refer to Patent Literatures 4, 5 and 6), however, further cost reduction and further enhancement of stability and conversion efficiency or the like are also desired thereon.    Patent Literature 1: JP No. 2664194    Patent Literature 2: WO 2002/011213    Patent Literature 3: JP-A-2002-164089    Patent Literature 4: JP-A-8-81222    Patent Literature 5: JP-A-11-214731    Patent Literature 6: JP-A-2001-52766    Non-patent Literature 1: B. O'Regan and M. Graetzel Nature, Vol. 353, p. 737 (1991)    Non-patent Literature 2: M. K. Nazeeruddin, A. Kay, I. Rodicio, R. Humphry-Baker, E. Muller, P. Liska, N. Vlachopoulos, M. Graetzel, J. Am. Chem. Soc., Vol. 115, p. 6382 (1993)    Non-patent Literature 3: W. Kubo, K. Murakoshi, T. Kitamura, K. Hanabusa, H. Shirai, and S. Yanagida, Chem. Lett., p. 1241 (1998)